This research is concerned with determining the organization of genetic information in the SV40 genome in order to define the process of transformation at the biochemical level. Adenovirus-SV40 hybrid viruses will be used to map SV40 functions and identify SV40-coded proteins in labeled, infected cells. New hybrids will be selected and the segment of SV40 DNA present will be localized in the SV40 physical map using heteroduplex methods. SV40 specific proteins present in cells infected with hybrids will be identified and such labeled protein will be used as markers in large scale purification of SV40 proteins from infected cells.